hi Alex sorry my english is not perfect.
i will try to explain better.
I know glamor is need for accelerations but if it is present i have glitched
video with fence error on rings 0 and 3 with gpu looked up.

i cant remove the nvidia without it the g5 quad dont boot.
anther important thing i forget to write.
if i put nouvau.modeset=1 and radeon.modeset=0 
xorg find the radeon and not the nvidia but because the modeset on radeon is
set to zero i dont have the xorg desktop.

i have exactly the specular situation that explained on the previous post.

Luigi